<template>
  <div>
    <h1>{{ currentIndex }}</h1>
    <div class="goods">
      <div class="menu-wrapper">
        <ul>
          <!-- current -->
          <li
            class="menu-item"
            v-for="(food, index) in foods"
            :key="index"
            :class="{current: index == currentIndex}"
            @click="leftNav(index)"
          >
            <span class="text bottom-border-1px">
              <img class="icon" :src="food.icon" v-if="food.icon" />
              {{ food.name }}
            </span>
          </li>
        </ul>
      </div>
      <div class="foods-wrapper">
        <ul ref="foodsUl">
          <li class="food-list-hook" v-for="(food, index) in foods" :key="index">
            <h1 class="title">{{ food.name }}</h1>
            <ul>
              <li
                class="food-item bottom-border-1px"
                v-for="(item, index) in food.foods"
                :key="index"
                @click="findFood(item)"
              >
                <div class="icon">
                  <img width="57" height="57" :src="item.icon" />
                </div>
                <div class="content">
                  <h2 class="name">{{ item.name }}</h2>
                  <p class="desc">{{ item.description }}</p>
                  <div class="extra">
                    <span class="count">月售{{ item.sellCount }}份</span>
                    <span>好评率{{ item.rating }}%</span>
                  </div>
                  <div class="price">
                    <span class="now">￥{{ item.price }}</span>
                    <span class="old" v-if="item.oldPrice">￥{{item.oldPrice}}</span>
                  </div>
                  <div class="cartcontrol-wrapper">
                    <ShopControl :food="item" />
                  </div>
                </div>
              </li>
            </ul>
          </li>
        </ul>
      </div>

      <!-- 购物车模块 -->
      <ShopCart />
      <!-- 商品信息模块 -->
      <FoodInfo ref="foodInfo" :food="food" />
    </div>
  </div>
</template>
 
<script>
import { mapState } from "vuex";
import ShopControl from "../../../components/CartControl/CartControl";
import ShopCart from "../../../components/ShopCart/ShopCart";
import FoodInfo from "../../../components/Food/Food";
import BScroll from "better-scroll";

export default {
  data() {
    return {
      foodsArray: [], // 右侧初识坐标值
      scrollY: 0, // 实时滚动的距离
      food: {}
    };
  },
  created() {
    // 请求商品数据
    this.$store.dispatch("getFoods", () => {
      this.$nextTick(function() {
        // 初始化 better-scroll
        this._initBetterScroll();
        // 初始化列表坐标
        this._initFoods();
      });
    });
  },
  computed: {
    ...mapState(["foods"]),
    // 计算当前滚动的下标
    currentIndex() {
      let index = this.foodsArray.findIndex((item, index) => {
        if (this.scrollY >= item && this.scrollY < this.foodsArray[index + 1]) {
          return true;
        }
      });
      return index;
    }
  },
  methods: {
    // 初始化 better-scroll
    _initBetterScroll() {
      this.$nextTick(() => {
        // 初始化better-scrioll 插件
        new BScroll(".menu-wrapper", {
          click: true
        });
        this.foodsScroll = new BScroll(".foods-wrapper", {
          probeType: 1
        });
        // 监听滚动的距离
        this.foodsScroll.on("scroll", ({ x, y }) => {
          this.scrollY = Math.abs(y);
        });

        // 监听停止滚动后的时间
        this.foodsScroll.on("scrollEnd", ({ x, y }) => {
          this.scrollY = Math.abs(y);
        });
      });
    },
    // 右侧坐标的初始值收集
    _initFoods() {
      const foodsLI = this.$refs.foodsUl.children;
      let temp = 0;
      this.foodsArray.push(temp);

      Array.prototype.slice.call(foodsLI).forEach(item => {
        temp += item.offsetHeight;
        this.foodsArray.push(temp);
      });
    },
    // 点击左边的菜单事件
    leftNav(index) {
      const { foodsArray } = this;
      this.scrollY = foodsArray[index];
      this.foodsScroll.scrollTo(0, -foodsArray[index]);
    },
    findFood(food) {
      this.food = food;
      // 调用FoodInfo 组件内部的方法
      this.$refs.foodInfo.toggleShow();
    }
  },
  components: {
    ShopControl,
    ShopCart,
    FoodInfo
  }
};
</script>
 
<style lang="stylus" rel="stylesheet/stylus">
@import '../../../common/stylus/minxins.styl';

.goods {
  display: flex;
  position: absolute;
  top: 287px;
  bottom: 46px;
  width: 100%;
  background: #fff;
  overflow: hidden;

  .menu-wrapper {
    flex: 0 0 80px;
    width: 80px;
    background: #f3f5f7;

    .menu-item {
      display: table;
      height: 54px;
      width: 56px;
      padding: 0 12px;
      line-height: 14px;

      &.current {
        position: relative;
        z-index: 10;
        margin-top: -1px;
        background: #fff;
        color: $green;
        font-weight: 700;

        .text {
          border-none();
        }
      }

      .icon {
        display: inline-block;
        vertical-align: top;
        width: 12px;
        height: 12px;
        margin-right: 2px;
        background-size: 12px 12px;
        background-repeat: no-repeat;
      }

      .text {
        display: table-cell;
        width: 56px;
        vertical-align: middle;
        bottom-border-1px(rgba(7, 17, 27, 0.1));
        font-size: 12px;
      }
    }
  }

  .foods-wrapper {
    flex: 1;

    .title {
      padding-left: 14px;
      height: 26px;
      line-height: 26px;
      border-left: 2px solid #d9dde1;
      font-size: 12px;
      color: rgb(147, 153, 159);
      background: #f3f5f7;
    }

    .food-item {
      display: flex;
      margin: 18px;
      padding-bottom: 18px;
      bottom-border-1px(rgba(7, 17, 27, 0.1));

      &:last-child {
        border-none();
        margin-bottom: 0;
      }

      .icon {
        flex: 0 0 57px;
        margin-right: 10px;
      }

      .content {
        flex: 1;

        .name {
          margin: 2px 0 8px 0;
          height: 14px;
          line-height: 14px;
          font-size: 14px;
          color: rgb(7, 17, 27);
        }

        .desc, .extra {
          line-height: 10px;
          font-size: 10px;
          color: rgb(147, 153, 159);
        }

        .desc {
          line-height: 12px;
          margin-bottom: 8px;
        }

        .extra {
          .count {
            margin-right: 12px;
          }
        }

        .price {
          font-weight: 700;
          line-height: 24px;

          .now {
            margin-right: 8px;
            font-size: 14px;
            color: rgb(240, 20, 20);
          }

          .old {
            text-decoration: line-through;
            font-size: 10px;
            color: rgb(147, 153, 159);
          }
        }

        .cartcontrol-wrapper {
          position: absolute;
          right: 0;
          bottom: 12px;
        }
      }
    }
  }
}
</style>
